How Vaccines Work

Babies and young children have always been a major focus of the vaccine move­ment. However, public health experts want to make sure that adolescents, adults and the elderly stay up-to­-date on their immunizations.

"Vaccines are not just for babies anymore," says Angie Matthiessen, MSW, of Immunize Georgia and Children's Healthcare of Atlanta. "Many adolescent and adult vaccines are now in place, often to protect the very young and elderly."

Some countries, such as the United States, have highly developed vaccine programs. As mentioned earlier, though, many diseases eradicated in the United States are still alive and well elsewhere. Many initiatives exist to reduce illness and death from vaccine-preventable diseases, such as the Measles Initiative Immunization program. This program is made up of partners like the World Health Organization (WHO), the CDC, the United Nations Foundation and UNICEF. A major success story is the decline of measles, largely in Africa. Worldwide deaths from measles fell 60 percent from 1999 to 2005. Most of these were in Africa, were measles deaths fell 75 percent. The decline is attributed to childhood immunization programs. Similar global programs exist for polio, pneumococcal disease and meningitis.

School requirements for vaccinations vary from state to state. The requirements for each state can be accessed here.

Travel requirements are pretty limited. International Health Regulations mandates that the yellow fever vaccination is necessary for travel to certain countries in tropical South America and sub-Saharan Africa. The Saudi Arabian government requires that visitors receive the meningococcal vaccination if visiting during the Hajj. Other than that, the CDC recommends that all international travelers be up-to-date on regular vaccinations. Whether or not travelers need extra vaccines depends on factors such as the destination country, season and whether rural areas will be visited. The CDC provides a comprehensive destination list for travelers to review here.